The invention relates to a method for forming a three-dimensional cell arrangement having a plurality of biological cells, in particular a method for setting or varying a geometric spatial configuration of a cell arrangement and methods for geometrically structuring cell material such as, for example, methods for so-called tissue engineering. The invention also relates to a device for carrying out these methods, in particular a substrate for a cell arrangement such as, for example, a cell culture or tissue, with which the geometric spatial configuration of a cell arrangement is adjustable or variable. The invention also relates to uses of the method and of the device.
In cell biology, biological cells typically undergo culturing (growth and/or differentiation) in an adherent state on a plane substrate. The advantage of culturing on the substrate is that the cells can then be adequately supplied with nutrients and the cells can be observed, e.g. using a microscope. One disadvantage is, however, that the adherent state on a substrate does not correspond to the conditions under which the cells naturally live. In the living organism, in particular in the living animal or human organism, cells form three-dimensional cell arrangements such as, for example, tissue or organs. In a three-dimensional cell arrangement the formation of cell-cell contacts in space means that the cells live under conditions different from those on a plane substrate. There is therefore interest in synthetically reproducing three-dimensional cell arrangements, in particular for purposes of the in vitro study of biological cells or medical cell therapy or tissue processing, in particular tissue engineering.
WO 2004/046337 proposes reproducing a three-dimensional cell arrangement by means of a structure consisting of layers of cells and biopolymer. In this structure the cells are spatially distributed in the biopolymer. One disadvantage of this technique is that conditions under which the cells naturally live can be created only to a limited extent. The biopolymers do not form the typical environment of the cells in living organisms. Further disadvantages are the limited shaping variability for the cell arrangement and the limited nutrient supply of the cells embedded in the biopolymer.
WO 2004/074425 discloses a method for geometrically forming cell material using an adjustable manipulation tool. A variant of this method is shown in FIG. 13. The cell material 1′ having a plurality of biological cells 2′ is arranged on a layered flexible substrate 10′. The shape of the substrate 10′ is variable with a drive apparatus 30′ and a plurality of shaping elements 31′. The substrate 10′ with the cell arrangement 1′ is arranged in a culturing vessel 40′ containing a culturing liquid 41′. The shape of the substrate 10′ can be set by displacing the shaping elements 31′, such that the cell material can be formed with a curved surface.
The practical use of the technique described in WO 2004/074425 may be limited as a result of the following disadvantages. First, engineering freedom is restricted by the movement of the shaping elements 31′. The drive apparatus 30′ cannot be used, for example, to create niches or cavities, yet these are of great interest for the replication of natural culturing conditions. Furthermore, the cells can grow only on the upper substrate face, since the lower substrate face is necessarily in contact with the shaping elements 31′. This gives rise to limitations in terms of the nutrient supply to the cells. Furthermore, the substrate can disrupt the natural culturing conditions of the cells in the cell material.
It is known from cell biology that cells exert attractive forces on substrates. US 2004/0033482 A1 proposes measuring the attractive forces by culturing cells on a pre-tensioned curved substrate. As a result of the attractive forces the substrate is bent back counter to the curvature, and curvature compensation is evaluated as a measure for the attractive forces.
The objective of the invention is to provide an improved method for forming a three-dimensional cell arrangement from biological cells, a method with which disadvantages of the conventional techniques are avoided and which, in particular, allows improved replication of conditions under which cells naturally live. A further objective of the invention is to provide an improved device for forming a three-dimensional cell arrangement with which limitations of the conventional techniques are overcome and which, in particular, has a widened field of use.
These objectives are achieved with a method and a device having the features of the invention.